2005/5/27 20:32 EDT. This rainbow is special in three ways:

1. The sun was setting. Its altitude was less than one degree! As a result, the rainbow was extrodinarily 'full', close to half a circle (recall the center of a rainbow and the sun are on the opposite sides of the sky).

2. The rainbow was more red than usual because of the setting sun was red. In fact colors other than red, which usually appear in normal rainbows, were hard to see in this rainbow. Those colors were absorbed/scattered away by the thick atmosphere light had to travel from the setting sun.

3. Notice the nice blue/red sky color contrast on two sides of the primary rainbow. This is an interesting display of Alexander's dark band. The geometry determines that rain drops inside the primary bow partially reflect sunlight back to an observer, while those immediately outside do not. The reflected sunlight was red because of the setting sun, while the sky was gray-blue outside.

I was expecting the rainbow when the western sky turned pink during the storm, and had my camera ready. To my disappointment the kit lens on Canon 300D could not take in the rainbow at once, even at widest zoom (18mm). From Green Tree, Pittsburgh.

Rainbow, Pittsburgh, 2005/5/27

the same rainbow, with a hint of secondary bow and Alexander's dark band